Controlled dosing of chlorine dioxide or other sanitizing agents into pressurized water systems

ABSTRACT

A medium having a support structure configured for circulation of a fluid therein, such as a replaceable filter cartridge, including a sanitizing agent which contains one or more reactants that are chemically configured for delivering chlorine dioxide or other sanitizing agents in a controlled dose to sanitize, deodorize, and disinfect upon being wetted by the fluid and positioned in the medium support structure to be exposed to the fluid circulating therein.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The subject application claims the benefit of priority to U.S.Provisional Patent Application No. 60/366,144, filed Mar. 20, 2002, thedisclosure of which is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a system and method of water treatment,and more particularly, to systems and methods of delivering controlleddoses of chlorine dioxide or other sanitizing agents into a pressurizedwater system.

2. Background of the Related Art

Potable water contains various levels of background contaminants such asHPC, pathogenic bacteria and algae, even after municipal treatment. Inmost instances, chlorine is used to reduce the concentration of suchbackground contaminants. Chlorine and chlorine compounds used forsanitization or disinfection are often removed from water supplies priorto use in drinking water systems, food service beverage systems and icedispensing equipment. The reasons for removal vary depending on theapplication or system. For example, the presence of chlorine in thewater supply to certain beverage systems may negatively impact aparticular quality of the beverage product, such as its taste.

There are also a significant amount of downstream potable water systemsthat do not use disinfection chemicals. This results in increased levelsof microorganisms and biofilm build-up. The build-up increases withindechlorination filters, resin beds, and other finely divided mediafilters during periods of stagnation. The build-up can be releaseddownstream at high levels causing health concerns, as well as severeoff-tastes and odors. Over a prolonged period of time biofilm coatswater lines and wetted parts of dispensing equipment, thus compoundingthe problem.

The concern generated by known high levels of microorganism build-up hascaused many in the food service and drinking water industry toperiodically sanitize water lines, often reaching the thresholdallowable by state or local regulations. Many of the sanitizationprocedures currently available are difficult to administer, costly,service intensive and use highly toxic chemicals. Some of the chemicalstypically used in these procedures include peroxide, chlorinederivatives, muric acid and citric acid. Although the desired sanitizingeffect may be achieved by these procedures, they are seldom implementeddue to the aforementioned problems.

Chlorine dioxide or other sanitizing agents have also been found to behighly effective as a sanitizer for use in potable water lines. Priortreatment procedures employed a highly concentrated solution of chlorinedioxide or other sanitizing agents, which is formed independently in aremote container and then pumped into the system lines. This solution isallowed to remain in the system lines for extended periods of time whilethe pressure in the water line is shut off.

One of the primary disadvantages of using chlorine dioxide or othersanitizing agents as a sanitizer according to prior treatment proceduresis the economic cost associated with the resulting system downtime sincethe system being sanitized is unusable during the treatment. Also, dueto the toxic nature of the chlorine dioxide or other sanitizing agentssolution, a specially trained service technician is often required toremain on-site until the solution is completely flushed out, thusfurther adding to the financial burden associated with these priortreatment procedures.

The flushing process itself often significantly extends the systemdowntime of the prior treatment procedures because of a residue left inthe system lines by the prolonged static exposure to the chlorine orother sanitizing agents solution. This residue is often difficult toremove, and even low levels of such residue may be considered toxic ornoxious, thus requiring the repeated flushing of the system.

It would be beneficial therefore, to provide a system and method fordelivering controlled doses of chlorine dioxide or other sanitizingagents into a pressurized water system, which overcomes the deficienciesof the prior art.

SUMMARY OF THE INVENTION

The present invention provides new and useful systems and methods fordelivering controlled doses of chlorine dioxide or other sanitizingagents into a pressurized potable water system which overcomes theproblems associated with the prior art.

A medium having a support structure with an inlet configured forreceiving a fluid, an outlet configured for delivering a fluid and abody configured for circulating a fluid therein, such as a replaceablefilter cartridge, which includes a sanitizing agent containing one ormore reactants that are chemically configured for releasing a compoundhaving sanitizing properties, such as chlorine dioxide, in a controlleddose upon being wetted by the fluid and positioned within the medium tobe exposed to the fluid circulating therein.

Preferably, the sanitizing agent releases chlorine dioxide or othersanitizing agents in specific amounts, at a specific and controlledconstant rate, to sanitize, deodorize, and disinfect equipment pipesconnected to the medium outlet. The rate of chlorine dioxide or othersanitizing agents release would be set to dilute in water with aconstant flow rate for a duration equivalent to perform the desiredtask, such as sanitize, deodorize, or disinfect water lines andequipment wetted parts.

The preferred mediums to be used in accordance with the presentinvention include systems or disposable cartridges. In particular, thepresent invention, is directed to a system for delivering a sanitizingagent to a fluid, which includes a substantially hollow vessel and asanitizing agent having one or more reactants which are chemicallyconfigured to release a compound having sanitizing properties uponexposure to the fluid. The hollow vessel includes an inlet passageconfigured for receiving fluid flow, an outlet passage configured forfluid egress, and an interior chamber configured for receiving fluidfrom the inlet passage and providing temporary confinement of the fluidtherein prior to egress from the outlet passage. The sanitizing agent isdisposed in the chamber and the confinement of water therein may beprovided by an independent valve.

The present invention is also directed to a filter cartridge thatincludes a hollow housing with a filter media chamber defined thereinand a sanitizing agent disposed in the filter media chamber. Thesanitizing agent preferably includes one or more reactants which arechemically configured to release a compound having sanitizing propertiesupon exposure to the fluid in the filter media chamber.

There can be inlet passage in the housing configured to provide fluidcommunication with the chamber and an outlet passage in the housingconfigured to provide fluid communication with the chamber. The fluid isdirected to the inlet passage and flows through the filter mediachamber, exiting the outlet passage with chlorine dioxide or othersanitizing agents from a portion of fluid included therewith having beenexposed to the sanitizing agent in the filter media chamber.

Preferably, the fluid is water and the compound is chlorine dioxide orother sanitizing agents, in which case, the one or more reactants caninclude a chlorite and the release of chlorine dioxide or othersanitizing agents is initiated by contact with the water. The chloritemay be an aqueous soluble chlorite selected from the group consisting ofsodium chlorite and potassium chlorite and mixtures thereof. Preferably,the one or more reactants include an aqueous soluble chlorite and anaqueous soluble acid. Preferably, the aqueous soluble acid is selectedfrom the group consisting of phosphoric acid, fumaric acid, glycolicacid, acetic acid, ascorbic acid, oxalic acid, maleic acid, lactic acid,tartaric acid, citric acid and mixtures thereof.

In addition, the system or filter cartridge of the present invention mayalso include a filtration media disposed in the chamber along with thesanitizing agent. The filtration media may be configured to providechemical or mechanical filtration depending on the application.Preferably, the filtration media and sanitizing agent are disposed inthe chamber and configured so that fluid entering the chamber is firstexposed to the filtration media prior to being exposed to the sanitizingagent and exiting the outlet.

In another embodiment which can be implemented in any medium (e.g.,cartridge or system) constructed in accordance with the presentinvention, a solution may be disposed in the chamber that includes asecond compound having sanitizing properties, such as chlorine. Thissolution is then mixed with fluid flowing in the chamber and exitsthrough the outlet passage.

In yet another embodiment which can be implemented in any mediumconstructed in accordance with the present invention, a substantiallyhollow neck is mated with the chamber. The neck has an inlet port influid communication with an inlet passage that is configured to be influid communication with the chamber, and an outlet port in fluidcommunication with an outlet passage that is also configured to be influid communication with the chamber. The inlet passage and outletpassage are both disposed in the neck and configured to provide dualfluid flow within the neck and independent fluid communication with thechamber.

The aforementioned embodiment may further include a tubular memberdisposed axially in the neck and having a portion with a porousperiphery extending into the chamber. The tubular member defines aninner axial passage therein and a radially outer axial passage boundedby the periphery of the tubular member and inner surface of the neck.Thus, the outer axial passage and the inner axial passage can providethe inlet and outlet passages, respectively. A filtration media may bedisposed along the porous periphery of the portion of the tubular memberextending into the filter media chamber and the sanitizing agent can bedisposed within the inner axial passage of the portion of the tubularmember extending into the chamber. Preferably, the sanitizing agent isseparated from the filtration media by an inert porous divider.

In yet another embodiment which can be implemented in any mediumconstructed in accordance with the present invention, a second outletport may be added to the housing or vessel at a position where it willbe in fluid communication with the chamber, and adjacent relative to theposition of the sanitizing agent within the chamber, so that a majorityor substantially all of the fluid exposed to the sanitizing agent exitsthis second outlet.

Further features of the subject invention will become more apparent fromthe detailed description of the present invention that follows taken inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art to which the presentapplication appertains will more readily understand how to make and usethe same, reference may be had to the drawings wherein:

FIG. 1 is a representative illustration of a system for providingcontrolled dosing of chlorine dioxide or other sanitizing agents tosanitize and clean equipment pipes or lines constructed in accordancewith a preferred embodiment of the present invention, which depicts thesystem including a dry sanitizing agent, which releases chlorine dioxideor other sanitizing agents upon wetting with water, and a liquidsanitizing agent and a filter head for connecting the system with theequipment;

FIG. 2 is a representative illustration of a filter cartridge forproviding controlled dosing of chlorine dioxide or other sanitizingagents to sanitize and clean equipment pipes or lines constructed inaccordance with a preferred embodiment of the present invention,including a dry sanitizing agent, which releases chlorine dioxide orother sanitizing agents upon wetting with water, a filtration media, afirst outlet for water exposed to the filtration media, and a secondoutlet for providing water exposed to the sanitizing agent; and

FIG. 3 is a representative illustration of a filter cartridge forproviding controlled dosing of chlorine dioxide or other sanitizingagents to sanitize and clean equipment pipes or lines constructed inaccordance with a preferred embodiment of the present invention,including a dry sanitizing agent, which releases chlorine dioxide orother sanitizing agents upon wetting with water and a filtration media,wherein the outlet stream from the filter cartridge contains a blend ofwater exposed to the filtration media and water exposed to thesanitizing agent.

These and other features of the subject invention will become morereadily apparent to those having ordinary skill in the art from thefollowing description of the preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the present invention,references are made to the accompanying drawings, which form a parthereof, and in which is shown by way of illustration specificembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is to be understood that otherembodiments may be utilized and that structural changes may be madewithout departing from the spirit and scope of the present invention.The following detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims and equivalents thereof.

The present invention provides vehicles, such as replaceable filtercartridges, for delivering chlorine dioxide or other sanitizing agentsto a water system in a variety of controlled doses periodically byexposure of the water in the system to sanitizing or cleaning agents.These agents may include stable dry chemicals such as, but not limitedto, those which are disclosed in the herein incorporated PublishedInternational Patent Application WO 01/60750A3 (PCT/US01/05002), capableof generating chlorine dioxide or other sanitizing agents when wetted.Preferably, the agent or agents release a specific amount of chlorinedioxide or other sanitizing agents, at a specific and controlledconstant rate. The rate of chlorine dioxide or other sanitizing agentsrelease would be set to dilute in water with a constant flow rate for aduration equivalent to clean (sanitize) water lines and equipment wettedparts.

Referring now to the drawings wherein like reference numerals identifysimilar structural features of the invention, there is illustrated inFIG. 1, a representative depiction of a stand-alone type system forproviding controlled dosing of sanitizer/cleaner into pressurized watersystems which is constructed in accordance with a preferred embodimentof the subject invention and designated generally by reference numeral10.

System 10 includes a pressure vessel 12 having a first end 14 and asecond end 16 defining a hollowed out, generally cylindrical chamber 18therein. First end 14 has a neck 20 which has an inlet port 22 in fluidcommunication with an inlet passage for directing fluid flow intochamber 18 according to arrow 24 (hereinafter referred to as “inletpassage 24”). Neck 20 also includes an outlet port 26 in fluidcommunication with an outlet tube 28 which extends axially into chamber18. In this embodiment, neck 20 also includes an optional bypass passagewhich provides fluid communication between inlet passage 24 and outletport 26 in accordance with arrow 30 (hereinafter referred to as “bypasspassage 30”).

Chamber 18 includes an unfilled region 32 adjacent first end 14, a firsttreatment region 34 containing a dry sanitizing agent 36 with controlledreaction dissolution and a second treatment region 38 containing aconcentrated sanitizing liquid 40 adjacent second end 16. Firsttreatment region 34 and second treatment region 38 are separated fromeach other by a porous inert divider 42. Sanitizing liquid 40 ispreferably chlorine and may also include a dye indicator forfacilitating awareness of its exhaustion.

System 10 is attachable to the water supply line (not shown) to a mastersystem (not shown), such as a beverage preparation device or ice makingmachine, via a filter head 44 having a first line 46 for receiving fluidfrom a supply line (not shown), a second line 48 for providing fluid tothe master system and a treatment device port 50. Filter head 44 may beconstructed with or retrofitted onto the supply line or any other linesin the master system. System 10 may also be connected to the mastersystem in other ways, such as by a permanent connection having flowcontrol valves. Treatment device port 50 separates first line 46 andsecond line 48 and to provide a space in which neck 20 of system 10 maybe inserted. Filter head 44 may also include a line pressure bypass withconstant flow rate. The flow rate may vary depending on the applicationbut typically ranges from about 0.25 gallons per minute to about 5.0gallons per minute.

Preferably, the outer periphery of neck 20 and the inner surface oftreatment device port 50 are configured to be engaged by correspondingcooperative structures defined respectively thereon. The cooperativestructures may consist of a proprietary interconnection Also, it ispreferable that neck 20 and treatment device port 50 be sealinglyengaged (e.g., using water resistant sealing rings fabricated of anelastomeric material) to maintain the integrity of fluid communicationbetween the first line 46 and inlet port 22, and between outlet port 26and second line 48, respectively.

Once system 10 is installed in filter head 44 (i.e., neck 20 is engagedwith treatment device port 50), water is provided to first line 46 andallowed to enter inlet port 22. A portion of the water flow enteringinlet port 22 will travel through inlet passage 24 into chamber 18 whilethe remaining portion of water flow will travel through bypass passage30. Bypass passage 30 is configured to direct the water flowing thereinthrough outlet port 26 sans treatment, to be diluted with the treatedwater also exiting from outlet port 26.

The water flowing through inlet passage 24 pours into unfilled region 32of chamber 18 creating turbulence as indicated by arrows 52 whichfacilitates better mixing of the untreated water and greater contactwith the sanitizers in treatment regions 34 and 38 within chamber 18.

The pressure of the incoming flow forces water within unfilled region 32through first treatment region 34, porous divider 42, and secondtreatment region 38 before exiting chamber 18 via outlet tube 28. As thewater passes through treatment regions 34 and 38, it is exposed to drysanitizing agent 36 and concentrated sanitizing liquid 40. The flow fromoutlet tube 28 mixes with untreated water flowing from outlet 26 viabypass passage 30 (if included) before being directed to the mastersystem via second line 48 in filter head 44. Preferably, for thisembodiment, the water flowing to the master system contains about 0.1parts per million of sanitizer to about 10 parts per million ofsanitizer after passage through system 10.

Another preferred embodiment of the present invention is represented bythe depiction in FIG. 2 of a filter cartridge having a separatesanitizer stream for providing controlled dosing of sanitizer/cleanerinto pressurized water systems, which is constructed in accordance withthe subject invention and designated generally by reference numeral 110.

System 110 includes a filter cartridge housing 112 having a first end114 and a second end 116 defining a hollowed out, generally cylindricalchamber 118 therein. First end 114 has a neck 120 which has an inletport 122 in fluid communication with an inlet passage for directingfluid flow into chamber 118 according to arrow 124 (hereinafter referredto as “inlet passage 124”). Neck 120 also includes an outlet port 126 influid communication with an outlet tube 128 extending axially intochamber 118. In this embodiment, filter cartridge housing 112 alsoincludes a separate sanitizer line 154 that draws fluid from chamber 118adjacent to second end 116 of filter cartridge housing 112.

Chamber 118 includes an axially disposed, radially porous center core156 and radially outer first treatment region 134 containing afiltration media 158 adjacent first end 114, which may be mechanical orchemical in nature (e.g., a peat block, screen, activated carbon block,sediment block, granular media, etc.), and which substantially surroundscenter core 156. Center core 156 includes a first open axial end 160adjacent to first end 114 of filter cartridge housing 112 and a secondopen axial end 162 adjacent to second end 116 of filter cartridgehousing 112.

The second open end 162 of center core 156 is adjacent to a secondtreatment region 138 containing a dry sanitizing agent 136 withcontrolled reaction dissolution. First treatment region 134 and secondtreatment region 138 are separated by a porous inert divider 142. Inaddition, filtration media 158 is configured and dimensioned to fitwithin filter cartridge housing 112 to define an unfilled annular region132 between the inner circumferential surface of chamber 118 and theouter periphery of filtration media 158 for fluid flow therebetween, asillustrated by arrows 164.

Filter cartridge 110 is attachable to a supply line (not shown),preferably located within the housing of a master system (not shown),such as a beverage preparation device or ice making machine. This may beaccomplished via a filter head (not shown) as in the previous embodimentor other connection having a port configured to engage neck 120.

When system 110 is in use, water pumped through the supply line entersinlet port 122 and flows into chamber 118 through inlet passage 124 inneck 120 of filter cartridge housing 112. As illustrated by arrows 164,the water flows through the unfilled annular region 132 and is pushedradially inward by the fluid pressure created in cartridge housing 112.The water is forced through filtration media 158 and into center core156. A portion of the water flow in center core 156 is directed towardsfirst end 114 and into outlet tube 128, eventually exiting filtercartridge housing 112 through outlet port 126, as illustrated by arrows166. Preferably, the majority of the water flow follows the path shownby arrows 166.

A portion of the water entering unfilled annular region 132 flowsaxially toward second end 116 in chamber 118 and into second treatmentregion 138 through porous inert divider 142 without passing throughfiltration media 158, as illustrated by arrow 168. A portion of thewater flow in center core 156 which has passed through filtration media158 is directed by pressure, or lack thereof, toward second end 116.This flow of treated water exits center core 156 from second open end162 and enters into second treatment region 138 through porous inertdivider 142, as illustrated by arrow 170. Water flowing within secondtreatment region 138 contacts dry sanitizing agent 136 and then exitsfilter cartridge housing 112 through separate sanitizer line 154. Thewater exposed to dry sanitizing agent 136 may be controlled by a controlvalve 172 in sanitizer line 154.

Another preferred embodiment of the present invention is represented bythe depiction in FIG. 3 of a filter cartridge having an encapsulatedsanitizing agent for providing controlled dosing of sanitizer/cleanerinto pressurized water systems, which is constructed in accordance withthe subject invention and designated generally by reference numeral 210.

System 210 includes a filter cartridge housing 212 having a first end214 and a second end 216 defining a hollowed out, generally cylindricalchamber 218 therein. First end 214 has a neck 220 which has an inletport 222 in fluid communication with an inlet passage for directingfluid flow into chamber 218 according to arrow 224 (hereinafter referredto as “inlet passage 224”). Neck 220 also includes an outlet port 226 influid communication with an outlet tube 228 extending axially intochamber 218.

Chamber 218 includes an axially disposed, radially porous center core256 and radially outer first treatment region 234 containing afiltration media 258 that extends axially substantially from first end214 to second end 216 and substantially surrounds center core 256.Filtration media 258 is configured and dimensioned to provide anunfilled annular region 232 between the inner circumferential surface ofchamber 218 and the outer periphery of filtration media 258 for fluidflow therebetween, as illustrated by arrows 264. Filtration media 258may be mechanical or chemical in nature (e.g., a peat block, screen,activated carbon block, sediment block, granular media, etc.).

Center core 256 includes an open axial end 260 adjacent to first end 214of filter cartridge housing 212 and a second treatment region 238containing a dry sanitizing agent 236 with controlled reactiondissolution adjacent to second end 216 of filter cartridge housing 212.An axially disposed porous inert divider 242 separates second treatmentregion 238 from the remaining portion of center core 256.

Filter cartridge 210 is attachable to a supply line (not shown),preferably located within the housing of a master system (not shown),such as a beverage preparation device or ice making machine. This may beaccomplished via a filter head (not shown) as in the previousembodiments or other connection having a port configured to engage neck220.

In use, water is pumped through supply line and flows from inlet port222 to chamber 218 through inlet passage 224 in neck 220 of filtercartridge housing 212. As illustrated by arrows 264, the water flowsthrough the unfilled annular region 232 and is pushed radially inward byfluid pressure. Water is forced through filtration media 258 and intocenter core 256, where it makes its way into outlet tube 228 and exitscartridge housing 212 through outlet port 226, as illustrated by arrows266.

A portion of the water flow forced through filtration media 258 alsoenters second treatment region 238 and contacts dry sanitizing agent236, as illustrated by arrow 268. The water exposed to dry sanitizingagent 236 flows through porous inert divider 242, as shown by arrows270, where it mixes with water which has not been treated by drysanitizing agent 236 before exiting filter cartridge housing 212, asdescribed above.

Preferably, predetermined amounts of dry sanitizing agent 236 isencapsulated in a sanitary cartridge such as cartridge 110 and 210, in away, that would allow the full flow of fluid therethrough. A suitableencapsulated sanitary cartridge configuration is manufactured by CunoIncorporated of Meriden, Conn., and sold under the tradename SQC® seriesdrinking water system.

System 10 and cartridges 110 and 210, or other similar devicesconstructed in accordance with the present invention, may have a varietyof end connector configurations to fit existing filter systems forperiodic insertion and activation, as well as proprietary interconnects.A system or cartridge constructed in accordance with the presentinvention can also be incorporated into master system downstream of anyabsorbent media and can be removed or left in place until replaced foranother treatment depending upon the filter head configuration.Furthermore, a system or cartridge of the present invention can be astandard component, which would be either supplied as part of a newinstallation, as a retrofit or as a replacement medium for chlorinedioxide or other sanitizing agents dosing.

Various doses of chlorine dioxide or other sanitizing agents may beadministered via the systems and cartridges of the present invention.For example, the periodic high dosing of chlorine dioxide or othersanitizing agents may be accomplished by utilizing predetermined amountsof a sanitizing agent that also allows full flow through the cartridge.Once installed, water can be introduced into a system or cartridge ofthe present invention is filled with the outlet port restricted. Oncewetted the agent would generate chlorine dioxide or other sanitizingagents within the cartridge for a predetermined period of time, until ahigh level (e.g., 50 parts per million to 100 parts per million) isdissolved into the water in the system or cartridge chamber. The outletport may be opened when ready and the chlorine dioxide or othersanitizing agents rich water can be forced by water pressure downstreaminto the water lines and equipment wetted parts, thereby strippingbiofilm therefrom.

The concentrated solution may be allowed to reach all exit ports of thedownstream equipment. Thereafter, the outlet line of the master systemcan be shut off. The chlorine dioxide or other sanitizing agents richsolution may be held for a predetermined amount of time (e.g., fromtwenty minutes to several hours) to facilitate the stripping of biofilmbuild-up in the master system lines and sanitize the water and wettedequipment parts. The master system can then be flushed for a prescribedamount of time so as to clear the water lines and cartridge of anyremaining chlorine dioxide or other sanitizing agents residue. One ofthe advantages of using chlorine dioxide or other sanitizing agents isits powerful oxidation capabilities and the ease by which residue isflushed out of the system.

For high dosing as described above, the rate of chlorine dioxide orother sanitizing agents generation is rapid, but its release from thecartridge or stand alone system can be set to dilute in water with aconstant flow rate, preferably between 50 parts per million and 100parts per million, for a duration equivalent to fill water lines andequipment wetted parts.

Low doses of chlorine dioxide or other sanitizing agents (i.e., about0.1 parts per million to about 0.5 parts per million) can also bedelivered into the water system periodically by exposure of the water inthe system to sanitizing or cleaning agents contained in a system orcartridge constructed in accordance with the present invention. Forexample, a low-level chlorine dioxide or other sanitizing agents dosingagent may be incorporated into a cartridge, such as cartridge 210, whichare constructed in accordance with the present invention, along withother reduction, removal or absorptive capabilities, or combinationsthereof. Upon installation, the agent can generate chlorine dioxide orother sanitizing agents at a low controlled rate for a short duration.Preferably, the chlorine dioxide or other sanitizing agents generationoccurs at a location that is downstream of any absorbent media withinthe same cartridge. As water enters the filter cartridge, chlorinedioxide or other sanitizing agents generation begins. The absorbent andreduction media would perform as normal for their prescribed life (e.g.,3 months, 6 months or 1 year), while the chlorine dioxide or othersanitizing agents generation would end within the first few minutes ofuse (e.g., from about 5 to about 20 minutes). The net result would bethe periodic sanitization of water lines and equipment wetted parts withthe convenience of a standard cartridge replacement.

In addition, a system or cartridge constructed in accordance with thepresent invention provides for the safe transportation and handling ofchlorine dioxide or other sanitizing agents producing agents, controlledlow level dosing rate in a dynamic flowing condition, controlled dosingduration, and system or cartridge formats and head assemblies which canintroduce chlorine dioxide or other sanitizing agents into a pressurizedwater line.

While the present invention has been described with respect to preferredembodiments, those skilled in the art will readily appreciate thatvarious changes and/or modifications can be made to the presentinvention with departing from the spirit or scope of the invention. Forexample, a filter cartridge may be constructed having a sanitizing agentin accordance with the present invention and with a bypass feature suchas, but not limited to, those filter cartridges which are disclosed inthe herein incorporated, copending and commonly owned U.S. patentapplication Ser. No. 10/337,832 filed on Jan. 7, 2003.

1. A system for delivering a sanitizing agent to a fluid, comprising: asubstantially hollow vessel having an inlet passage configured forreceiving fluid flow, an outlet passage configured for fluid egress, andan interior chamber configured for receiving fluid from the inletpassage and providing temporary confinement of the fluid therein priorto egress from the outlet passage; a sanitizing agent operativelydisposed in the chamber, the sanitizing agent including one or morereactants which are chemically configured to release a compound havingsanitizing properties upon exposure to the fluid in the chamber; and asolution operatively disposed in the chamber of the vessel including asecond compound having sanitizing properties, wherein the solution ismixed with fluid in the chamber for egress through the outlet passage.2. A filter cartridge comprising: a hollow housing with a filter mediachamber defined therein; a substantially hollow neck mated with thefilter media chamber having an inlet port in fluid communication with aninlet passage configured to be in fluid communication with the filtermedia chamber and an outlet port in fluid communication with an outletpassage configured to be in fluid communication with the filter mediachamber, wherein the inlet passage and outlet passage are disposed inthe neck and configured to provide dual fluid flow within the neck andindependent fluid communication with the filter media chamber; asanitizing agent disposed in the filter media chamber, the sanitizingagent including one or more reactants which are chemically configured torelease a compound having sanitizing properties upon exposure to thefluid in the filter media chamber; and a tubular member disposed axiallyin the neck and having a portion with a porous periphery extending intothe filter media chamber, the tubular member defining an inner axialpassage therein and a radially outer axial passage bounded by theperiphery of the tubular member and inner surface of the neck, whereinthe outer axial passage and the inner axial passage provide the inletand outlet passages, respectively.
 3. A filter cartridge as recited inclaim 2, further comprising a filtration media disposed along the porousperiphery of the portion of the tubular member extending into the filtermedia chamber.
 4. A filter cartridge as recited in claim 3, wherein thesanitizing agent is disposed within the inner axial passage of theportion of the tubular member extending into the filter media chamber.5. A filter cartridge as recited in claim 3, wherein the sanitizingagent is separated from the filtration media by an inert porous divider.6. A filter cartridge as recited in claim 5, further comprising a secondoutlet port in the housing in fluid communication with the filter mediachamber and disposed adjacent relative to the position of the sanitizingagent within the filter media chamber for receiving a majority of thefluid exposed to the sanitizing agent.